I offered to replace the cracked parging on the basement sills when I had new PVC windows done.recently Problem: The OLD windows were thicker, in part because of a wooden sill then jams which were added after the window was installed. Then parging was added. The NEW windows were butted up to the gyproc, shimmed only on the bottom with 2 or 3 narrow pieces of plywood then foamed. This leaves a gap of about 2 inches of 'missing' parging.
The surplus foam I can trim back but some shim blocks stick out too far to achieve the correct slope for parging. Can they be shortened to about 3/4" and left in the new parging?
I want to get this done then top up the foaming on the jams because the installer's attitude seems to be 'hide the bits that don't fit with aluminum trim' which he'll add when he returns. Draft-proofing is not on his agenda. I had to insist I was allowed to top up the gaps in insulation IN the wall & frame - put 2 shopping bags worth in eventually.

Thanks for your encouraging reply.
I'll reword the question in short sentences.

It's regarding finishing the parging on new basement windows without compromising their attachment to the house.
Focus on the bottom edge of a 3 pane window - FCF.
The OLD windows took up 7 inches from the inside trim to the outside wooden sill. To ensure rain run-off, parging had been added to this sill.

The NEW windows take up only 4 inches from inside to outside.
This leaves a significant gap (between new window & old parging) which has to be filled.
The aluminum trim will be put into a narrow grove around each window and bent to match the parging then caulked.

The problem is how to deal with the excess of foam and the plywood shims without making the window less securely attached.
These shims are the only solid support for the windows - no shims were put in the sides or top.
They were stacked in 2s and 3s but are too long so they'd be sticking out of any parging which has to slope away.
4 screws were used for attachment in the middle frame of the 3 pane window, otherwise it's only foam keeping it in place.
I'll be glad to hear how anyone has dealt with this problem.

I deal with this CACA every day. Cut off the shims,cap the mess and move on.
Let your installer do his job and do not help anymore unless it kills you.
If it looks good and does the job then you should be satisfied I think.
Let me get this straight you used spray foam?
What the heck is parging? I just gotta know.

Dear Handyman,
............"do not help any more unless it kills you" ?? What sort of answer is that? Maybe you've had a long day, but a web site like this is for people to share their concerns and get helpful feed back from both sides, customers and contractors.
I think I expessed a concern that I was being railroaded by an installer who just wanted to install, hide the air leaks and go. He was happy for me to parge - see below. The window & door foam was what he used to hold in the windows, plus 4 screws - not much for a 57 inch wide window.

Parging, by the way, is a cement-like bonding material used to finish exterior surfaces. When used for basement windows it seals the cut surface of the foundation wall where windows have been installed and it slopes in order to shed the rain.

I'm going to end this exchange since I think you've offered all you know.

Other than picturing a 57" wide basement window, unless this is a split level home, I think I have a pretty clear picture of what you're talking about, having replace basement windows before, removing the frame and all.

Cant you 2) trim the shims so they to do not protrude beyand the width of the frame, b) fill the gaps with fibergllas insuation and then seal with the foam, which in my mind's eye seem like it would give you enough room to repair/replace your parging?

I think you'll have to be very precise at pointing that surface to keep it flush and uniform with the present surface, but it should look good.

I can kind of picture what I think your talking about but I'm a bit unclear. Usually when I do a basement window I remove all the BS stuff all around the opening. I'm assuming your into concrete poured walls or block. If so the new window should have been ordered to correctly span that entire opening. If your installer wants to wrap the window off then just make sure he has some nice and squared areas to work on. The metal is easier bent in straight bends with no interference from protruding obstacles. If your doing what we call here in MN a skim coat over urethane insulation. You'll have your work cut out for yourself. You'll need a J-bead edging to butt the window when applying. This gives you a good straight line to caulk the window to. I myself would wrap the entire unit. Much easier to do and less time involved. good luck!

HipKat & Guy,
How nice to read your helpful replies! I've followed through - cut the plywood shims with a flexible japanese pull-saw so I could get close to the new frame without nicking it and trimmed the foam that was too high.
The 3/8th inch deep groove all around the new window is where the aluminum trim will be inserted to finish off, so to keep it free of parging I folded a length of (gyprocking) paper tape and tucked it in, turned it up and tapped it. Easy to remove later. Then I applied a cement bonding coat and skim coat as you say - guess my parging comes from my UK background, though we call it that here in Canada too.
Anyway, I'm pleased with the job so far. Thanks again.

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